A resin composition containing an aromatic polycarbonate resin and a polyester resin has a high level of an appearance, excellent mechanical properties, dimensional stability and chemical resistance and is hence widely used in various industrial fields. In particular, with regard to a resin composition containing an aromatic polycarbonate resin and a polyethylene terephthalate resin (to be sometimes referred to as “PC/PET alloy” hereinafter), various resin compositions are under study (see Patent Documents 1, 2 and 3). Since the PC/PET alloy has properties achieved by combining the excellent impact resistance, mechanical properties and dimensional stability of an aromatic polycarbonate resin with the chemical resistance of a polyethylene terephthalate resin, it is effectively used in particular in the fields of interior and exterior automotive trims and OA equipment and machines.
In recent years, in the fields of automotive trims and OA equipment and machines, a rapid decrease in part thickness and a rapid decrease in part weight are in progress. For example, the technical development of resin materials that are to be used for producing large parts typified by body panels such as a fender is again actively made for a decrease in weight in the automotive field, and these parts requiring a decrease in thickness and weight are increasingly required to have heat resistance and moist heat resistance more than ever. Further, it is required to decrease the number of parts for reducing costs, and such resin materials are now required to have moldability for meeting with the integration of parts and the consequent complicated and large forms, i.e., excellent thermal stability.
Under the circumstances, an alloy material using PET produced in the presence of a specific polymerization catalyst is proposed as means by which PC/PET alloy satisfies the above requirements (see Patent Documents 4 and 5). Patent Document 4 proposes the use of a germanium catalyst in order to overcome that degradation of the color tone, melt stability, appearance and moldability which is found in PET produced in the presence of an antimony compound or titanium compound which is generally used as a polymerization catalyst. However, its outcome is not satisfactory with regard to the moist heat resistance and thermal stability that are required in the field of automotive use, and further improvements are required.
Patent Document 5 proposes that a polyester resin produced in the presence of 1 to 30 ppm of a titanium-containing catalyst compound be incorporated in order to improve the color tone, thermal stability and melt stability. Since the catalyst amount is reduced, the thermal stability and melt stability are improved. However, with an increase in the amount of the polyester resin, the thermal stability tends to be decreased, and further improvements are required. Further, Patent Document 5 teaches nothing concerning the finding of the moist heat resistance of a resin composition comprising an aromatic polycarbonate resin and a polyester resin which is increasingly required to attain.
Patent Document 6 describes that a polyester resin having an excellent color tone (b value), a decreased amount of foreign matter and excellent thermal stability during melting can be produced by using a titanium-containing catalyst having a specific structure. However, it does not refer to any effect on a resin composition containing a different resin other than a polyester resin, nor does it teach anything concerning the finding of the moist heat resistance of a resin composition comprising an aromatic polycarbonate resin and a polyester resin which is increasingly required to attain.
As described above, in the PC/PET alloy, there is desired a material which maintains good thermal stability and at the same time has high moist heat resistance and which is excellent in chemical resistance, impact strength, heat resistance and rigidity.    (Patent Document 1) JP36-14035B    (Patent Document 2) JP39-20434B    (Patent Document 3) JP59-176345A    (Patent Document 4) JP51-102043A    (Patent Document 5) JP2005-521772A    (Patent Document 6) Japanese Patent No. 3897756 (WO2003/008479)